Grammy and Oscar winner Jennifer Hudson was called as the first witness today in the murder trial of William Balfour, the man accused of shooting her mother Darnell Donerson (57), brother Jason Hudson (29), and nephew Julian King (7) in 2008.

At the time of the shooting, Balfour was married to Hudson's elder sister, Julia, though the two were estranged.

Hudson testified that she and other family members had been against the relationship of Balfour and her sister from the beginning.

"I would tell her (Julia) over and over again not to marry William."

"None of us wanted her to marry him. We did not like how he treated her."

Balfour and Julia Hudson were married in December 2006, without the knowledge of Jennifer or Jason Hudson, or their mother. The couple, along with Julia Hudson's then six-year-old son, moved into the house in which the Hudson children had been raised in Chicago's South Side.

Julia Hudson testified that Balfour threatened to kill her family after she separated from him in 2008, allegedly telling her:

"If you leave me, you'll be the last to die. I'm going to kill your family first."

Jennifer Hudson flew to Chicago on October 24, 2008, after learning her mother and brother had been killed, and that her seven-year-old nephew was missing. Three days later, Julian King's body was found abandoned in the backseat of the white SUV Hudson had bought for her brother, miles away from the site of his mother and uncle's murders.

Authorities believe William Balfour stole the vehicle, then shot his step-son in the head as the second grader lay behind a front seat.

Jennifer Hudson was called in to the morgue to identify all three bodies.